Impact-absorbing steering column apparatus

ABSTRACT

Collision-energy-absorbing means of an impact-absorbing steering column apparatus includes guide slots  31   a   1  and  31   b   1 , guide slots  31   a   2  and  31   b   2 , and transition portions  31   a   3  and  31   b   3 , as well as energy-absorbing members  36  and  37 , so as to change absorption load for secondary collision energy. A collar  42  plastically deforms the energy-absorbing member  36  or  37 , thereby absorbing secondary collision energy of an occupant in the event of a collision of a vehicle. The guide slots  31   a   1  and  31   b   1 , the guide slots  31   a   2  and  31   b   2 , and the transition portions  31   a   3  and  31   b   3  change an absorption load for secondary collision energy dependently on the direction of a secondary collision of the occupant with the steering system.

TECHNICAL FIELD

The present invention relates to an impact-absorbing steering columnapparatus having collision-energy-absorbing means for absorbingsecondary collision energy of an occupant (driver) in the event of acollision of a vehicle.

BACKGROUND ART

A conventional impact-absorbing steering column apparatus effectsabsorption of secondary collision energy such that column drive meanscauses a steering column to retreat in relation to an occupant inaccordance with the distance between the occupant and a steering wheelor the position of the steering column in relation to the occupant orsuch that energy absorption quantity adjustment means varies, inaccordance with the distance or the position, the quantity of secondaryimpact energy to be absorbed by collision-energy-absorbing means. Suchan impact-absorbing steering column apparatus is disclosed in, forexample, Japanese Patent Application Laid-Open (kokai) No. 2002-79944.

The above-mentioned conventional impact-absorbing steering columnapparatus is configured such that the column drive means and the energyabsorption quantity adjustment means are operated under the control ofan electrical control unit. The distance between the occupant and thesteering wheel or the position of the steering column in relation to theoccupant is electrically detected. On the basis of the detected distanceor position, at least either the column drive means or the energyabsorption quantity adjustment means is electrically controlled. Thus, aproblem of high cost is involved.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished in order to solve the aboveproblem, and an object of the invention is to change an absorption loadfor secondary collision energy of an occupant in the event of asecondary collision of the occupant with a steering system, by means ofa mechanical action effected by the secondary collision.

An aspect of the present invention provides an impact-absorbing steeringcolumn apparatus comprising collision-energy-absorbing means forabsorbing secondary collision energy of an occupant in the event of acollision of a vehicle. The collision-energy-absorbing means comprisesenergy-absorption-load-changing means for changing an absorption loadfor the secondary collision energy. The energy-absorption-load-changingmeans is adapted to change the absorption load in accordance withdisplacement of a steering column, the displacement changing dependentlyon a secondary collision of the occupant with a steering system.

According to the present invention, for example, in the event of acollision of the vehicle, the occupant moves in a certain directiontoward the front of the vehicle while having certain kinetic energy,depending on whether or not the occupant wears a seat belt, a collisionspeed, a seat position, and like factors; and a certain secondarycollision load is input to the steering system along a certain directionof a secondary collision.

Thus, the energy-absorption-load-changing means of thecollision-energy-absorbing means can change the absorption load forsecondary collision in accordance with displacement of the steeringcolumn, the displacement changing dependently on a secondary collisionof the occupant with the steering system. In other words, in accordancewith the direction of the secondary collision of the occupant with thesteering system and/or the magnitude of the collision load, the steeringcolumn is displaced or allowed to be readily displaced in a directiondifferent from a direction along which the steering column moves inrelation to the vehicle body toward the front of the vehicle whileabsorbing energy. By means of association of displacement of thesteering column with an action of the energy-absorption-load-changingmeans, an absorption load to be generated by theenergy-absorption-load-changing means can be changed in accordance withthe displacement of the steering column.

Another aspect of the present invention provides an impact-absorbingsteering column apparatus comprising collision-energy-absorbing meansfor absorbing secondary collision energy of an occupant in the event ofa collision of a vehicle. The collision-energy-absorbing means comprisesenergy-absorption-load-changing means for changing an absorption loadfor the secondary collision energy. The energy-absorption-load-changingmeans is adapted to change the absorption load in accordance withdisplacement of the steering column in a direction intersecting adirection of relative movement of the steering column for absorbingcollision energy induced by a secondary collision of the occupant.

According to the present invention, for example, in the event of acollision of the vehicle, the occupant moves in a certain directiontoward the front of the vehicle while having certain kinetic energy,depending on whether or not the occupant wears a seat belt, a collisionspeed, a seat position, and like factors; and a certain secondarycollision load is input to the steering system along a certain directionof a secondary collision.

Thus, by utilizing displacement of the steering column in a directionintersecting a direction along which the steering column moves inrelation to the vehicle body toward the front of the vehicle whileabsorbing collision energy, the energy-absorption-load-changing meansadapted to absorb energy can change an absorption load. In other words,in accordance with the direction of the secondary collision of theoccupant with the steering system and/or the magnitude of the collisionload, the steering column is displaced or allowed to be readilydisplaced in a direction different from a direction along which thesteering column moves in relation to the vehicle body toward the frontof the vehicle while absorbing energy. By means of association ofdisplacement of the steering column with an action of theenergy-absorption-load-changing means, an absorption load to begenerated by the energy-absorption-load-changing means can be changed inaccordance with the displacement of the steering column.

According to a further aspect of the present invention, theenergy-absorption-load-changing means changes the absorption load inaccordance with a mode of displacement of the steering column. Accordingto the present invention, for example, an absorption load to begenerated by the energy-absorption-load-changing means is changed inaccordance with a mode of displacement of the steering column, so thatthe absorption load can be changed in accordance with the displacedposition of the steering column.

According to a further aspect of the present invention, theenergy-absorption-load-changing means comprises an energy-absorbingmember, and engagement means capable of engaging with theenergy-absorbing member, and an engagement relation between theenergy-absorbing member and the engagement means varies in accordancewith a mode of displacement of the steering column, thereby changing theabsorption load. According to the present invention, for example, theengagement relation between the energy-absorbing member and theengagement means can be varied in accordance with a mode of displacementof the steering column, whereby the absorption load can be changed.

According to a further aspect of the present invention, the engagementmeans is squeezing means for squeezing the energy-absorbing member; theenergy-absorbing member has an energy-absorbing portion, which issqueezed by the squeezing means to thereby absorb energy; and anengagement relation between the squeezing means and the energy-absorbingportion varies in accordance with a mode of displacement of the steeringcolumn, thereby changing the absorption load. According to the presentinvention, for example, the engagement relation between the squeezingmeans and the energy-absorbing portion is varied in accordance with amode of displacement of the steering column, whereby the absorption loadcan be changed.

According to a further aspect of the present invention, the engagementmeans is squeezing means for squeezing the energy-absorbing member; theenergy-absorbing member has a plurality of energy-absorbing portionsthat differ in energy absorption load in relation to the squeezingmeans; and an engagement between the squeezing means and one of theplurality of energy-absorbing portions is selected in accordance with amode of displacement of the steering column, thereby changing theabsorption load. According to the present invention, for example, anengagement between the squeezing means and one of the plurality ofenergy-absorbing portions is selected in accordance with a mode ofdisplacement of the steering column, whereby the absorption load can bechanged.

According to a further aspect of the present invention, the engagementmeans is squeezing means for squeezing the energy-absorbing member; thesqueezing means has a plurality of squeezing portions that differ in thequantity of draw/squeeze in squeezing the energy-absorbing member; andan engagement between the energy-absorbing member and one of theplurality of squeezing portions is selected in accordance with a mode ofdisplacement of the steering column, thereby changing the absorptionload. According to the present invention, for example, an engagementbetween the squeezing means and one of the plurality of squeezingportions is selected in accordance with a mode of displacement of thesteering column, whereby the absorption load can be changed.

According to a further aspect of the present invention, theenergy-absorbing member is a linear member capable of engaging with theengagement means; the engagement means is engaged with or is not engagedwith the linear member in accordance with a mode of displacement of thesteering column, thereby changing the absorption load. According to thepresent invention, for example, the engagement means is engaged with oris not engaged with the linear member in accordance with a mode ofdisplacement of the steering column, whereby the absorption load can bechanged.

According to a further aspect of the present invention, theenergy-absorbing member is a plurality of linear members capable ofengaging with the engagement means; the number of the linear members tobe engaged with the engagement means varies in accordance with a mode ofdisplacement of the steering column, thereby changing the absorptionload. According to the present invention, for example, the number of thelinear members to be engaged with the engagement means varies inaccordance with a mode of displacement of the steering column, wherebythe absorption load can be changed.

According to a further aspect of the present invention, the steeringcolumn comprises the energy-absorbing member, a ball adapted toplastically deform the energy-absorbing member, and ball support meansfor adjusting the quantity of plastic deformation to be effected by theball; and the ball support means is moved in accordance with a mode ofdisplacement of the steering column in such a manner as to vary anengagement relation between the energy-absorbing member and the ball inaccordance with the mode, thereby changing the absorption load.According to the present invention, for example, the ball support meansis moved in such a manner as to vary the engagement relation between theenergy-absorbing member and the ball in accordance with a mode ofdisplacement of the steering column, whereby the absorption load can bechanged.

According to a further aspect of the present invention, theenergy-absorbing member has an elongated groove having a predeterminedwidth; the engagement means is squeezing means assuming a special shapeand capable of being displaced in the elongated groove in relation tothe energy-absorbing member; and an engagement relation between thespecial-shape squeezing means and the elongated groove of theenergy-absorbing member varies in accordance with a mode of displacementof the steering column, thereby changing the absorption load. Accordingto the present invention, for example, the engagement relation betweenthe special-shape squeezing means and the elongated groove of theenergy-absorbing member varies in accordance with a mode of displacementof the steering column, whereby the absorption load can be changed.

According to a further aspect of the present invention, anenergy-absorbing member is provided on either a vehicle-body-side memberor the steering column, the energy-absorbing member generating an energyabsorption load by means of displacement in relation to either thevehicle-body-side member or the steering column on which theenergy-absorbing member is provided; the engagement means capable ofengaging with the energy-absorbing member is provided on either thevehicle-body-side member or the steering column on which theenergy-absorbing member is not provided; and when the energy-absorbingmember is engaged with the engagement means in accordance with a mode ofdisplacement of the steering column, the mode changing dependently on asecondary collision, the energy-absorbing member incrementally changesthe absorption load by means of displacement in relation to either thevehicle-body-side member or the steering column on which theenergy-absorbing member is provided. According to the present invention,for example, when the energy-absorbing member is engaged with theengagement means in accordance with a mode of displacement of thesteering column, the mode of displacement changing dependently on asecondary collision, the energy-absorbing member can incrementallychange the absorption load by means of displacement in relation toeither the vehicle-body-side member or the steering column on which theenergy-absorbing member is provided.

According to a further aspect of the present invention, theenergy-absorption-load-changing means changes the absorption load inaccordance with displacement of the steering column, the displacementchanging dependently on the direction of a secondary collision of theoccupant with the steering system. According to the present invention,for example, the energy-absorption-load-changing means can change theabsorption load in accordance with displacement of the steering column,the displacement changing dependently on the direction of a secondarycollision of the occupant with the steering system.

According to a further aspect of the present invention, theenergy-absorption-load-changing means changes the absorption load inaccordance with displacement of the steering column, the displacementchanging dependently on the direction of a secondary collision of theoccupant with the steering system at an initial stage of the secondarycollision. According to the present invention, for example, theenergy-absorption-load-changing means can change the absorption load inaccordance with displacement of the steering column, the displacementchanging dependently on the direction of a secondary collision of theoccupant with the steering system at an initial stage of the secondarycollision.

According to a further aspect of the present invention, when a collisionload associated with a secondary collision of the occupant with thesteering system is equal to or greater than a predetermined value, theenergy-absorption-load-changing means increases the absorption load.According to the present invention, for example, when a collision loadassociated with a secondary collision of the occupant with the steeringsystem is equal to or greater than a predetermined value, theenergy-absorption-load-changing means can increase the absorption load.

According to a further aspect of the present invention, theenergy-absorption-load-changing means increases the absorption load inaccordance with such displacement that the steering column tilts upwardas a result of a secondary collision of the occupant with the steeringsystem. According to the present invention, for example, theenergy-absorption-load-changing means can increase the absorption loadin accordance with such displacement that the steering column tiltsupward as a result of a secondary collision of the occupant with thesteering system.

According to a further aspect of the present invention, theenergy-absorption-load-changing means changes the absorption load inaccordance with a direction of displacement of the steering column, thedirection of displacement changing dependently on the direction of asecondary collision of the occupant with the steering system. Accordingto the present invention, for example, theenergy-absorption-load-changing means can increase the absorption loadin accordance with the displaced position of the steering column, thedisplaced position changing dependently on the direction of a secondarycollision of the occupant with the steering system.

According to a further aspect of the present invention, impact-absorbingmeans for absorbing a predetermined collision load is providedseparately from the collision-energy-absorbing means. According to thepresent invention, for example, the impact-absorbing means for absorbinga predetermined collision load can be provided separately from thecollision-energy-absorbing means.

According to a further aspect of the present invention, thecollision-energy-absorbing means selectively provides the absorptionload, or changes the magnitude of the absorption load. According to thepresent invention, for example, the collision-energy-absorbing means candetermine whether to effect the absorption load or can change themagnitude of the absorption load.

According to a further aspect of the present invention, in accordancewith a load of pressing the steering column against a vehicle-body-sidemember and a load of moving the steering column toward the front of thevehicle, the loads changing dependently on a secondary collision of theoccupant with the steering system, deformation of an energy-absorbingmember provided on either the steering column or the vehicle-body-sidemember is passively changed by engagement means provided on either thesteering column or the vehicle-body-side member on which theenergy-absorbing member is not provided, whereby theenergy-absorption-load-changing means changes the absorption load.According to the present invention, for example, in accordance with aload of pressing the steering column against the vehicle-body-sidemember and a load of moving the steering column toward the front of thevehicle, the loads changing dependently on a secondary collision of theoccupant with the steering system, deformation of the energy-absorbingmember provided on either the steering column or the vehicle-body-sidemember is passively changed by the engagement means provided on eitherthe steering column or the vehicle-body-side member on which theenergy-absorbing member is not provided, whereby the absorption load canbe changed.

According to a further aspect of the present invention, the engagementmeans is formed on the vehicle-body-side member; the energy-absorbingmember is provided on the steering column in opposition to theengagement means and assumes an elongated shape extending along an axisof the steering column; and the engagement means provided on thevehicle-body-side member causes the deformation of the energy-absorbingmember provided on the steering column. According to the presentinvention, for example, the engagement means is formed on thevehicle-body-side member; the energy-absorbing member is provided on thesteering column in opposition to the engagement means and assumes anelongated shape extending along the axis of the steering column; and theengagement means provided on the vehicle-body-side member can cause thedeformation of the energy-absorbing member provided on the steeringcolumn.

According to a further aspect of the present invention, only when acollision load imposed on the vehicle-body-side member from the steeringcolumn is equal to or greater than a predetermined value, abutmentbetween the engagement means and the energy-absorbing member is enabled.According to the present invention, for example, only when a collisionload imposed on the vehicle-body-side member from the steering column isequal to or greater than a predetermined value, the engagement means canabut the energy-absorbing member.

According to a further aspect of the present invention, in the event ofa secondary collision, the steering column is allowed to be displaced insuch a manner as to tilt toward the vehicle-body-side member. Accordingto the present invention, for example, in the event of a secondarycollision, the steering column can be displaced in such a manner as totilt toward the vehicle-body-side member.

According to a further aspect of the present invention, the absorptionload is increased with a load of pressing the steering column againstthe vehicle-body-side member. According to the present invention, forexample, the absorption load can be increased with the load of pressingthe steering column against the vehicle-body-side member.

According to a further aspect of the present invention, impact-absorbingmeans for absorbing a predetermined collision load is providedseparately from the collision-energy-absorbing means. According to thepresent invention, for example, the impact-absorbing means for absorbinga predetermined collision load can be provided separately from thecollision-energy-absorbing means.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view showing a first embodiment of an impact-absorbingsteering column apparatus according to the present invention;

FIG. 2 is an enlarged side view showing essential portions of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged plan view of a steering mounting member shown inFIGS. 1 to 3;

FIG. 5 is an enlarged side view partially showing a steering column, anupper support mechanism, and a lower support mechanism shown in FIGS. 1and 2;

FIG. 6 is a vertical, longitudinal sectional view showing theconfigurational relation among a support bracket, energy-absorbingmembers, a bush, a collar, and a bolt, among others shown in FIG. 3;

FIG. 7 is an explanatory view for explaining the action of essentialportions when the steering column moves frontward in the event of acollision of the vehicle in the case of an occupant wearing a seat belt;

FIG. 8 is an explanatory view for explaining the action of essentialportions when the steering column moves frontward in the event of acollision of the vehicle in the case of the occupant not wearing theseat belt;

FIG. 9 is a side view showing essential portions of a modification ofthe first embodiment;

FIG. 10 is a side view showing a second embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 11 is a plan view of the steering column assembly shown in FIG. 10;

FIG. 12 is a vertical, transverse sectional view showing theconfigurational relation between energy-absorbing members and engagementpins shown in FIG. 10;

FIG. 13 is an explanatory view for explaining an action in the event ofinput of a secondary collision load in the direction of the column axisinto the steering column assembly shown in FIG. 10;

FIG. 14 is an explanatory view for explaining an action in the event ofinput of a secondary collision load substantially in the horizontaldirection into the steering column assembly shown in FIG. 10;

FIG. 15 is a side view showing a third embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 16 is a plan view of the steering column assembly shown in FIG. 15;

FIG. 17 is a vertical, transverse sectional view showing theconfigurational relation between energy-absorbing members and anengagement hook shown in FIG. 15;

FIG. 18 is an explanatory view for explaining an action in the event ofinput of a secondary collision load in the direction of the column axisinto the steering column assembly shown in shown in FIG. 15;

FIG. 19 is an explanatory view for explaining an action in the event ofinput of a secondary collision load substantially in the horizontaldirection into the steering column assembly shown in FIG. 15;

FIG. 20 is a side view showing a fourth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 21 is a plan view of the steering column assembly shown in FIG. 20;

FIG. 22 is a vertical, transverse sectional view showing theconfigurational of an upper support mechanism shown in FIG. 20;

FIG. 23 is an explanatory view for explaining an action in the event ofinput of a secondary collision load in the direction of the column axisinto the steering column assembly shown in FIG. 20;

FIG. 24 is an explanatory view for explaining an action in the event ofinput of a secondary collision load substantially in the horizontaldirection into the steering column assembly shown in FIG. 20;

FIG. 25 is a side view showing a fifth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 26 is a plan view of the steering column assembly shown in FIG. 25;

FIG. 27 is a vertical, transverse sectional view showing theconfigurational relation between balls and a ring shown in FIG. 25 and arod capable of engaging with an arm of the ring;

FIG. 28 is a series of vertical, transverse sectional views showingengagement relations between the rod and the arm of the ring shown inFIG. 27;

FIG. 29 is an explanatory view for explaining an action in the event ofinput of a secondary collision load in the direction of the column axisinto the steering column assembly shown in FIG. 25;

FIG. 30 is an explanatory view for explaining an action in the event ofinput of a secondary collision load substantially in the horizontaldirection into the steering column assembly shown in FIG. 25;

FIG. 31 is an enlarged vertical, transverse sectional view showing theconfigurational relation between the balls and engagement grooves formedin a lower column as viewed when the ring shown in FIG. 27 is rotated bymeans of the rod;

FIG. 32 is a side view showing a sixth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 33 is a vertical, longitudinal sectional view showing theconfigurational relation between an upper energy-absorbing member and areinforcement plate of a support bracket shown in FIG. 32;

FIG. 34 is a vertical, transverse sectional view showing theconfigurational relation between the upper energy-absorbing member andthe reinforcement plate of the support bracket shown in FIG. 32;

FIG. 35 is an explanatory view for explaining an action in the casewhere the upper component of a secondary collision load input to asteering column of the steering column assembly shown in FIG. 32 issmall;

FIG. 36 is an explanatory view for explaining an action in the casewhere the upper component of the secondary collision load input to thesteering column of the steering column assembly shown in FIG. 32 islarge;

FIG. 37 is a side view showing a seventh embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 38 is a plan view of the steering column assembly shown in FIG. 37;

FIG. 39 is a vertical, longitudinal sectional view showing theconfigurational relation between an upper energy-absorbing member and areinforcement plate of a support bracket shown in FIG. 37;

FIG. 40 is a vertical, transverse sectional view showing theconfigurational relation between the upper energy-absorbing member andthe reinforcement plate of the support bracket shown in FIG. 37;

FIG. 41 is an explanatory view for explaining an action in the casewhere the upper component of a secondary collision load input to asteering column of the steering column assembly shown in FIG. 37 issmall;

FIG. 42 is an explanatory view for explaining an action in the casewhere the upper component of the secondary collision load input to thesteering column of the steering column assembly shown in FIG. 37 islarge;

FIG. 43 is a side view showing an eighth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 44 is a plan view of the steering column assembly shown in FIG. 43;

FIG. 45 is a vertical, longitudinal sectional view showing theconfigurational relation between an upper energy-absorbing member and asupport bracket shown in FIG. 43;

FIG. 46 is a vertical, transverse sectional view showing theconfigurational relation between the upper energy-absorbing member andthe support bracket shown in FIG. 43;

FIG. 47 is an explanatory view for explaining an action as viewed at itsinitial stage in the case where the upper component of a secondarycollision load input to a steering column of the steering columnassembly shown in FIG. 43 is small;

FIG. 48 is an explanatory view for explaining an action as viewed at itsintermediate stage in the case where the upper component of thesecondary collision load input to the steering column of the steeringcolumn assembly shown in FIG. 43 is small;

FIG. 49 is an explanatory view for explaining an action as viewed at itsinitial stage in the case where the upper component of the secondarycollision load input to the steering column of the steering columnassembly shown in FIG. 43 is large;

FIG. 50 is an explanatory view for explaining an action as viewed at itsintermediate stage in the case where the upper component of thesecondary collision load input to the steering column of the steeringcolumn assembly shown in FIG. 43 is large;

FIG. 51 is a side view showing a ninth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 52 is a plan view of the steering column assembly shown in FIG. 51;

FIG. 53 is a vertical, longitudinal sectional view showing theconfigurational relation between an upper energy-absorbing member and asupport bracket shown in FIG. 51;

FIG. 54 is a vertical, transverse sectional view showing theconfigurational relation between the upper energy-absorbing member andthe support bracket shown in FIG. 51;

FIG. 55 is an explanatory view for explaining an action as viewed at itsinitial stage in the case where the upper component of a secondarycollision load input to a steering column of the steering columnassembly shown in FIG. 51 is small;

FIG. 56 is an explanatory view for explaining an action as viewed at itsintermediate stage in the case where the upper component of thesecondary collision load input to the steering column of the steeringcolumn assembly shown in FIG. 51 is small;

FIG. 57 is an explanatory view for explaining an action as viewed at itsinitial stage in the case where the upper component of the secondarycollision load input to the steering column of the steering columnassembly shown in FIG. 51 is large;

FIG. 58 is an explanatory view for explaining an action as viewed at itsintermediate stage in the case where the upper component of thesecondary collision load input to the steering column of the steeringcolumn assembly shown in FIG. 51 is large;

FIG. 59 is a side view showing a tenth embodiment of theimpact-absorbing steering column apparatus according to the presentinvention;

FIG. 60 is a plan view of the steering column assembly shown in FIG. 59;

FIG. 61 is a vertical, longitudinal sectional view showing theconfigurational relation between an upper energy-absorbing member and asqueezing plate provided on a reinforcement plate of a support bracketin an upper support mechanism shown in FIG. 59;

FIG. 62 is a vertical, transverse sectional view showing theconfigurational relation between the upper energy-absorbing member andthe squeezing plate provided on the reinforcement plate of the supportbracket in the upper support mechanism shown in FIG. 59;

FIG. 63 is an explanatory view for explaining an action in the casewhere the upper component of a secondary collision load input to asteering column of the steering column assembly shown in FIG. 59 issmall; and

FIG. 64 is an explanatory view for explaining an action in the casewhere the upper component of the secondary collision load input to thesteering column of the steering column assembly shown in FIG. 59 islarge.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will next be described in detailwith reference to the drawings. FIGS. 1 to 8 show a first embodiment ofan impact-absorbing steering column apparatus according to the presentinvention. In the first embodiment, a steering column 12 supports asteering shaft 11 rotatably and in an axially unmovable condition and issupported by a steering mounting member 20, which is a portion of avehicle body, at a predetermined tilt angle by means of an upper supportmechanism A and a lower support mechanism B.

The lower end (front end) of the steering shaft 11 is linked to anintermediate shaft 14, which can extend and contract and can transmittorque, via a universal joint 13. A steering wheel 17, into which anairbag device is incorporated, is attached to the upper end (rear end)of the steering shaft 11 in a unitarily rotatable condition.

The upper support mechanism A is adapted to support an upper region ofthe steering column 12. During ordinary use, the upper support mechanismA supports the upper region of the steering column 12 such that thesteering column 12 can be vertically moved for adjustment (the tilt ofthe steering column 12 can be adjusted). In the event of a secondarycollision that accompanies a collision of the vehicle, the upper supportmechanism A supports the upper region of the steering column 12 suchthat the steering column 12 can tilt upward and can move frontward alongits axis. As shown in FIGS. 1 to 3, the upper support mechanism Aincludes a support bracket 31 made of an iron plate, a column-sidebracket 32 made of an iron plate, clamp means 40, and an operation lever50 used to operate the clamp means 40. The support bracket 31 haslaterally paired arms 31 a and 31 b extending downward and is fixedlyattached to the steering mounting member 20 by use of laterally pairedmounting bolts 39. The column-side bracket 32 has laterally paired arms32 a and 32 b extending upward and is welded to the steering column 12.The clamp means 40 is adapted to frictionally engage the arms 32 a and32 b of the column-side bracket 32 with the arms 31 a and 31 b of thesupport bracket 31 in a fixed condition or to disengage them.

As shown in FIGS. 1 to 4, the steering mounting member 20 has a mountingportion 21 in its upper region for attachment of the upper supportmechanism A and a mounting portion 22 in its lower region for attachmentof the lower support mechanism B. As shown in FIG. 3, the mountingportion 21 for the upper support mechanism A has a substantiallyU-shaped cross section, and a substantially V-shaped convex surface S1located at its lower end. Laterally paired bolt insertion holes 21 b and21 c are formed in the mounting portion 21 and allow the correspondingmounting bolts 39 to extend therethrough. Laterally paired nuts 23 and24 into which the corresponding mounting bolts 39 are screwed are weldedto the mounting portion 21 in alignment with the bolt insertion holes 21b and 21 c, respectively.

As shown in FIGS. 3 and 6, the support bracket 31 is composed of a plate31A and a reinforcement plate 31B. The plate 31A has a substantiallyM-shaped cross section, and a substantially V-shaped concave surface S2located at its top and coming into close contact with the substantiallyV-shaped convex surface S1 of the steering mounting member 20. Thereinforcement plate 31B is welded to laterally opposite lower endportions of the plate 31A so as to reinforce the plate 31A. The plate31A includes the laterally paired arms 31 a and 31 b extending downward.Laterally paired bolt insertion holes 31 c (see FIG. 6) are formed inthe plate 31A and allow the corresponding mounting bolts 39 to extendtherethrough. As shown in FIGS. 1 and 2, laterally paired guide slots 31a 1 and 31 b 1 extending frontward and laterally paired guide slots 31 a2 and 31 b 2 extending frontward are formed in the arms 31 a and 31 b.

As shown in FIGS. 1, 2, and 6, the lower guide slots 31 a 1 and 31 b 1are formed linearly, substantially in parallel with the axial directionof the steering column 12. The lower guide slots 31 a 1 and 31 b 1 andthe corresponding upper guide slots 31 a 2 and 31 b 2 communicate witheach other via corresponding transition portions 31 a 3 and 31 b 3located at rear end portions of the guide slots. As shown in FIG. 6, theupper guide slots 31 a 2 and 31 b 2 are formed linearly and extendupward at a predetermined angle θ with respect to the correspondinglower guide slots 31 a 1 and 31 b 1.

As shown in FIGS. 1, 2, 3, and 5, the column-side bracket 32 includesthe laterally paired arms 32 a and 32 b, which extend upward and areslidably engaged with the corresponding arms 31 a and 31 b of thesupport bracket 31 from the outside. Arcuately elongated holes 32 a 1and 32 b 1 are formed in the corresponding arms 32 a and 32 b arcuatelyabout support center O1 of the lower support mechanism B.

As shown in FIGS. 1 to 3, the clamp means 40 includes a nonrotatablelock bolt 41, a collar 42, a nut 43, and a pair of laterally adjacentcam plates 44. The lock bolt 41 extends through the arcuately elongatedholes 32 a 1 and 32 b 1 formed in the laterally opposite arms 32 a and32 b of the column-side bracket 32 and through the guide slots 31 a 1and 31 b 1 or the guide slots 31 a 2 and 31 b 2 formed respectively inthe laterally opposite arms 31 a and 31 b of the support bracket 31. Thecollar 42 is fitted onto the lock bolt 41 while extending between thelaterally opposite arms 32 a and 32 b of the column-side bracket 32 andis fitted, at its laterally opposite end portions, into the guide slots31 a 1 and 31 b 1 or the guide slots 31 a 2 and 32 b 2. The nut 43 isscrewed on an externally threaded portion 41 a of the lock bolt 41 androtated by means of the operation lever 50. The paired cam plates 44 aremounted on the lock bolt 41 between the operation lever 50 and the leftarm 32 a of the column-side bracket 32. The detailed configuration ofthe paired, laterally adjacent cam plates 44 is the same as hatdescribed in Japanese Patent Application Laid-Open (kokai) No.2000-62624; therefore, repeated description thereof is omitted.

The clamp means 40 functions as follows. When the operation lever 50 isrotated counterclockwise in FIG. 1, the nut 43 is fastened to the lockbolt 41, and the paired cam plates 44 convert rotation of the operationlever 50 to an axial stroke of the lock bolt 41. As a result, apredetermined frictional engagement is established between the arms 31 aand 32 a of the brackets 31 and 32 and between the arms 31 b and 32 b ofthe brackets 31 and 32, whereby the column-side bracket 32 is fixed(locked) to the support bracket 31. When the operation lever 50 isrotated clockwise in FIG. 1, the nut 43 is loosened, and thus the abovefrictional engagement is canceled. As a result, the column-side bracket32 becomes tiltable in relation to the support bracket 31.

In the first embodiment, as shown in FIGS. 3 and 6, a support plate 35is attached to the support bracket 31, and vertically pairedenergy-absorbing members 36 and 37 are also attached to the supportbracket 31. The support plate 35 extends laterally within the supportbracket 31 and is welded, at its laterally opposite ends, to the arms 31a and 31 b of the support bracket 31.

The lower energy-absorbing member 36 is provided for use with the lowerguide slots 31 a 1 and 31 b 1, and is a thin elongated plate having apredetermined width (a plate whose absorption load is small whenabsorbing secondary collision energy). In the event of a secondarycollision that accompanies a collision of the vehicle, when thecolumn-side bracket 32 moves frontward by a set value or more inrelation to the support bracket 31 and thus the lock bolt 41 and thecollar 42 move frontward along the guide slots 31 a 1 and 31 b 1, theenergy-absorbing member 36 is squeezed by the lock bolt 41 and thecollar 42 and plastically deformed, thereby absorbing secondarycollision energy. The energy-absorbing member 36 is welded, at its rearend, to the support plate 35 and welded, at its front end, to the uppersurface of the reinforcement plate 31B of the support bracket 31.

The upper energy-absorbing member 37 is provided for use with the upperguide slots 31 a 2 and 31 b 2, and is a thick elongated plate having apredetermined width (a plate whose absorption load is large whenabsorbing secondary collision energy). In the event of a secondarycollision that accompanies a collision of the vehicle, when thecolumn-side bracket 32 moves frontward by a set value or more inrelation to the support bracket 31 and thus the lock bolt 41 and thecollar 42 move frontward along the guide slots 31 a 2 and 31 b 2, theenergy-absorbing member 37 is squeezed by the lock bolt 41 and thecollar 42 and plastically deformed, thereby absorbing secondarycollision energy. The energy-absorbing member 37 is welded, at its rearend, to the support plate 35 and welded, at its front end, to the lowersurface of the upper wall of the plate 31A of the support bracket 31.

The lower support mechanism B is adapted to support a lower region ofthe steering column 12. During ordinary use, the lower support mechanismB supports the lower region of the steering column 12 in a tiltable(pivotable) condition. In the event of a secondary collision thataccompanies a collision of the vehicle, the lower support mechanism Bsupports the steering column 12 such that the steering column 12 canmove frontward along its axis. As shown in FIGS. 1, 2, and 5, the lowersupport mechanism B is composed of a vehicle-body-side bracket 61 madeof an iron plate, a column-side bracket 62 made of an iron plate, andconnection means 70. The vehicle-body-side bracket 61 includes laterallypaired arms 61 a extending downward and is fixed to the steeringmounting member 20. The column-side bracket 62 has a cross sectionresembling a squarish letter U and is welded to the steering column 12at an upper portion of the column's outer circumferential surface in thecolumn's lower region. The connection means 70 connects the column-sidebracket 62 to the vehicle-body-side bracket 61 such that the column-sidebracket 62 is movable along the column axis and tiltable.

The connection means 70 is composed of laterally paired resin bushes 71and 72, a collar 73, a bolt 74, and a nut (welded to the right-hand armof the vehicle-body-side bracket 61), into which the bolt 74 is screwedin a fixed condition. The bushes 71 and 72 are fitted to correspondinglaterally paired elongated holes 62 a formed in the column-side bracket62 and extending along the column axis and break under a predeterminedload. The collar 73 is fitted into the resin bushes 71 and 72 andengaged, at its opposite ends, with the arms 61 a of thevehicle-body-side bracket 61. The bolt 74 extends through the collar 73and through round mounting holes formed in the corresponding arms 61 aof the vehicle-body-side bracket 61 and unites the resin bushes 71 and72 and the collar 73 with the vehicle-body-side bracket 61.

In the first embodiment, as shown in FIG. 1, a seat belt device 90 isattached to a seat 80 for an occupant H. The seat belt device 90includes a seat belt 91, a tongue plate 92, a buckle 93, and a shoulderbelt anchor 94, as well as a retractor 95 into which a pretensionermechanism and a force limiter mechanism are incorporated. When theoccupant H wears the seat belt 91, the seat belt 91 can restrain theoccupant H.

In the thus-configured first embodiment, when the clamp means 40 of theupper support mechanism A is unlocked by means of rotating the operationlever 50 clockwise in FIGS. 1 and 2, the frictional engagement iscanceled between the arms 31 a and 32 a of the brackets 31 and 32 andbetween the arms 31 b and 32 b of the brackets 31 and 32. Thus, thesteering column 12 becomes movable (tiltable) by a predetermined amountalong the elongated holes 32 a 1 and 32 b 1 of the column-side bracket32. Since the lower support mechanism B always allows the column-sidebracket 62 to move in a tilting condition in relation to thevehicle-body-side bracket 61, the tilt of the steering wheel 17 can beadjusted by means of vertically moving the steering column 12 within atiltable range.

When the clamp means 40 of the upper support mechanism A is locked bymeans of rotating the operation lever 50 counterclockwise in FIGS. 1 and2, a predetermined frictional engagement is established between the arms31 a and 32 a of the brackets 31 and 32 and between the arms 31 b and 32b of the brackets 31 and 32, whereby the column-side bracket 32 is fixedto the support bracket 31. Thus, the steering column 12 is fixedlysupported by the steering mounting member 20, which is a portion of avehicle body, at a predetermined tilt angle by means of the uppersupport mechanism A and the lower support mechanism B.

For example, in the event of a collision of the vehicle while theoccupant H wears the seat belt 91, the first embodiment functions asfollows. Since the occupant H is restrained by the seat belt 91, theoccupant H moves frontward while bending himself/herself forward. At theinitial stage of a secondary collision of this case, a collision loadfrom the occupant H is exerted on the steering column 12 in thedirection of F1 (along the axis of the steering column 12) in FIG. 2 viathe steering wheel 17 and the steering shaft 11. As a result of thecollision load overcome the above-mentioned frictional engagement and arupture load of the bushes 71 and 72, the steering column 12 movesfrontward along its axial direction.

When the steering column 12 moves frontward along its axial direction,as shown in FIG. 7, the lock bolt 41 and the collar 42 in the uppersupport mechanism A move frontward along the guide slots 31 a 1 and 31 b1, thereby plastically deforming the lower energy-absorbing member 36.The plastic deformation yields a small absorption load for secondarycollision energy. In this case, the seat belt device 90 functions; andan air bag device incorporated in the steering wheel 17, and theenergy-absorbing member 36, which is provided for use with the lowerguide slots 31 a 1 and 31 b 1 in the upper support mechanism A, functionsequentially, thereby absorbing secondary collision energy of theoccupant H.

In the event of a collision of the vehicle while the occupant H does notwear the seat belt 91, since the occupant H is not restrained by theseat belt 91, the occupant H moves frontward inertially. As a result, atthe initial stage of a secondary collision of this case, a collisionload is exerted on the steering column 12 in the direction of F2 in FIG.2. As a result of the collision load overcome the above-mentionedfrictional engagement and the rupture load of the bushes 71 and 72, thesteering column 12 moves frontward along its axial direction while beingdisplaced in a tilting-upward manner.

In this case, in the upper support mechanism A, the lock bolt 41 and thecollar 42 move from rear end portions of the lower guide slots 31 a 1and 31 b 1 to rear end portions of the upper guide slots 31 a 2 and 31 b2 via the transition portions 31 a 3 and 31 b 3. Subsequently, as shownin FIG. 8, the lock bolt 41 and the collar 42 move frontward along theupper guide slots 31 a 2 and 31 b 2, thereby plastically deforming theupper energy-absorbing member 37. The plastic deformation yields a largeabsorption load for secondary collision energy. In this case, the airbag device incorporated in the steering wheel 17, and theenergy-absorbing member 37, which is provided for use with the upperguide slots 31 a 2 and 31 b 2 in the upper support mechanism A, functionsequentially, thereby absorbing secondary collision energy of theoccupant H.

As described above, according to the first embodiment, in the event of acollision of the vehicle, in accordance with, for example, whether ornot the occupant H wears the seat belt 91, the occupant H movesfrontward in a certain direction while having certain kinetic energy;and a certain secondary collision load (for example, F1 or F2) is inputto the steering column 12 along a certain direction of a secondarycollision. Thus, at the initial stage of a secondary collision of theoccupant H with the steering system, the steering column 12 is displacedin the direction of the secondary collision while being guided by theguide slots provided in the support bracket 31; specifically, by theguide slots 31 a 1 and 31 b 1, the guide slots 31 a 2 and 31 b 2, andthe transition portions 31 a 3 and 31 b 3. The displacement causes theenergy-absorbing member 36 provided for use with the guide slots 31 a 1and 31 b 1 or the energy-absorbing member 37 provided for use with theguide slots 31 a 2 and 31 b 2 to function, whereby in the event of asecondary collision an absorption load for secondary collision energy ischanged.

As described above, according to the first embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the guide slots 31 a 1and 31 b 1, the guide slots 31 a 2 and 31 b 2, and the transitionportions 31 a 3 and 31 b 3 provided in the support bracket 31 changesthe absorption load by means of a mechanical action effected inaccordance with the direction of a secondary collision of the occupant Hwith the steering system. In other words, the first embodiment can bemechanically implemented by means of appropriately setting, for example,the shape of the guide slots 31 a 1 and 31 b 1, the shape of the guideslots 31 a 2 and 31 b 2, the shape of the transition portions 31 a 3 and31 b 3, and the shape of the energy-absorbing members 36 and 37, withoutneed to employ electrical control, whose cost is high, and thus at lowcost.

In the above-described first embodiment, the lower energy-absorbingmember 36 is formed of a thin, elongated plate having a predeterminedwidth, and the upper energy-absorbing member 37 is formed of a thick,elongated plate having a predetermined width. However, theenergy-absorbing members 36 and 37 may be embodied as follows: the lowerenergy-absorbing member 36 is formed of a narrow, elongated plate havinga predetermined thickness, and the upper energy-absorbing member 37 isformed of a wide, elongated plate having the predetermined thickness.

According to the above-described first embodiment, the present inventionis embodied in relation to a steering column assembly having a tiltfunction. However, the present invention may be similarly embodied inrelation to a steering column assembly having no tilt function. In theabove-described first embodiment, two pairs of guide slots 31 a 1 and 31b 1, and 31 a 2 and 31 b 2, are provided in the support bracket 31, andthe energy-absorbing members 36 and 37 are provided for use with thecorresponding guide slots. However, the number of guide slots and thenumber of energy-absorbing members may be increased as appropriate.

In the above-described first embodiment, two pairs of guide slots 31 a 1and 31 b 1, and 31 a 2 and 31 b 2, and two kinds of correspondingenergy-absorbing members 36 and 37 are provided in the support bracket31, which is a vehicle-body-side member in the upper support mechanismA. However, the following configuration may be employed: two guide meansare provided in the column-side bracket 32, which is a column-sidemember in the upper support mechanism A, and two kinds ofenergy-absorbing members are provided which correspond to these guidemeans. In this case, a support shaft (a member corresponding to the lockbolt 41) is fixedly attached to a vehicle-body-side support bracket.

In the above-described first embodiment, collision-energy-absorbingmeans, which includes two pairs of guide slots 31 a 1 and 31 b 1, and 31a 2 and 31 b 2, and two kinds of energy-absorbing members 36 and 37, isprovided in the upper support mechanism A. However, a configurationshown in FIG. 9 may be employed; specifically, thecollision-energy-absorbing means, which includes two pairs of guideslots 31 a 1 and 31 b 1, and 31 a 2 and 31 b 2, and two kinds ofenergy-absorbing members 36 and 37, is provided in the lower supportmechanism B. In this case, the rear end of the energy-absorbing member36 is welded to the upper surface of the steering column 12, and therear end of the energy-absorbing member 37 is welded to the lowersurface of the upper wall of the column-side bracket 62.

In the above-described first embodiment, the energy-absorbing members 36and 37, which are plastically deformed by means of the lock bolt 41 andthe collar 42 to thereby absorb secondary collision energy, are formedof corresponding elongated plates provided separately from the supportbracket 31. However, the following configuration may be employed: theguide slots 31 a 1 and 31 b 1 and the guide slots 31 a 2 and 31 b 2formed in the support bracket 31 assume different widths such that theguide slot portions are plastically deformed by means of the lock bolt41 and the collar 42 to thereby absorb secondary collision energy.

According to the above-described first embodiment, the present inventionis embodied in relation to a steering column assembly configured suchthat an upper region of the steering column 12 is supported by the uppersupport mechanism A in a frontward movable condition, and a lower regionof the steering column 12 is supported by the lower support mechanism Bin a frontward movable condition. However, the present invention may besimilarly embodied in relation to a steering column assembly configuredsuch that a steering column is supported by a single support mechanismin a frontward movable condition.

FIGS. 10 to 14 show a second embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the secondembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes laterally pairedenergy-absorbing members 101 and 102 provided in the upper supportmechanism A, engagement pins 103 and 104 provided on the steering column12, and an energy-absorbing member 105 provided in the lower supportmechanism B. Structural features other than thecollision-energy-absorbing means for absorbing secondary collisionenergy of the occupant H are substantially identical with those of theabove-described first embodiment and are thus denoted by commonreference numerals, and repeated description thereof is omitted.

The laterally paired energy-absorbing members 101 and 102 are elongatedplates. When the engagement pin 103 or 104 is engaged with theenergy-absorbing members 101 and 102 and passes frontward therebetween,the energy-absorbing members 101 and 102 are plastically deformed tothereby absorb secondary collision energy. The energy-absorbing members101 and 102 are formed integrally with the reinforcement plate 31B ofthe support bracket 31 in the upper support mechanism A. Theenergy-absorbing members 101 and 102 face each other with apredetermined gap formed therebetween and extend along the axialdirection of the steering column 12.

The engagement pins 103 and 104 are provided on the steering column 12in such a manner as to project upward. Stoppers 103 a and 104 a areintegrally formed at distal end portions of the engagement pins 103 and104, respectively. The main purpose of the stoppers 103 a and 104 a isto prevent the engagement pin 103 or 104 from coming out of the gapbetween the energy-absorbing members 101 and 102 when the engagement pin103 or 104 is fitted into the gap and moves frontward through the gap.

The distal engagement pin 103 has a diameter slightly greater than thegap between the energy-absorbing members 101 and 102. When the steeringcolumn 12 tilts upward by θ1 from the condition of FIG. 10 and movesfrontward, the engagement pin 103 can be fitted into the gap between theenergy-absorbing members 101 and 102. The engagement pin 103 fitted intothe gap between the energy-absorbing members 101 and 102 can plasticallydeform the energy-absorbing members 101 and 102.

The proximal engagement pin 104 has a diameter slightly greater thanthat of the distal engagement pin 103. When the steering column 12 tiltsupward by θ2 (θ1<θ2) from the condition of FIG. 10 and moves frontward,the engagement pin 104 can be fitted into the gap between theenergy-absorbing members 101 and 102. The engagement pin 104 fitted intothe gap between the energy-absorbing members 101 and 102 can plasticallydeform the energy-absorbing members 101 and 102.

As shown in FIG. 13, the energy-absorbing member 105 provided in thelower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 105 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 105 is fixedly attached, at its one end portion 105 a, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured second embodiment, in the event of asecondary collision that accompanies a collision of the vehicle; forexample, when, as shown in FIG. 13, a secondary collision load is inputto the steering column 12 in the direction of the arrow (in thedirection of the column axis) via the steering shaft 11, the steeringcolumn 12 moves frontward along its axial direction. In this case, whileneither of the engagement pins 103 and 104 is fitted into the gapbetween the energy-absorbing members 101 and 102, the energy-absorbingmember 105 is plastically deformed by means of the collar 73. As aresult, since secondary collision energy is absorbed by means of plasticdeformation of only the energy-absorbing member 105 caused by the collar73, an absorption load for secondary collision energy is small.

In the event of a secondary collision that accompanies a collision ofthe vehicle; for example, when, as shown in FIG. 14, a secondarycollision load is input to the steering column 12 in the direction ofthe arrow (substantially in the horizontal direction) via the steeringshaft 11, the steering column 12 tilts upward in response to a secondarycollision load exerted in the direction of the arrow at the initialstage of the secondary collision and subsequently moves frontward alongits axial direction.

Thus, the distal engagement pin 103 is fitted into the gap between theenergy-absorbing members 101 and 102 to thereby plastically deform theenergy-absorbing members 101 and 102, while the energy-absorbing member105 is plastically deformed by means of the collar 73. In this case,since secondary collision energy is absorbed by means of plasticdeformation of the energy-absorbing members 101 and 102 caused by thedistal engagement pin 103 and plastic deformation of theenergy-absorbing member 105 caused by the collar 73, an absorption loadfor secondary collision energy is larger than that in the case of FIG.13.

In the case where, as a result of input of a large secondary collisionload in the direction of the arrow of FIG. 14, the steering column 12tilts upward more than in the condition shown in FIG. 14 andsubsequently moves frontward along its axial direction, the proximalengagement pin 104 is fitted into the gap between the energy-absorbingmembers 101 and 102 to thereby plastically deform the energy-absorbingmembers 101 and 102, while the energy-absorbing member 105 isplastically deformed by means of the collar 73. In this case, sincesecondary collision energy is absorbed by means of plastic deformationof the energy-absorbing members 101 and 102 caused by the proximalengagement pin 104 and plastic deformation of the energy-absorbingmember 105 caused by the collar 73, an absorption load for secondarycollision energy is larger than that in the case of FIG. 14.

As described above, according to the second embodiment, in the event ofa secondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the engagement pins 103and 104 changes an absorption load for secondary collision energy inaccordance with the direction and load of a secondary collision of theoccupant H with the steering system. In other words, the secondembodiment can be mechanically implemented by means of appropriatelysetting, for example, the shape and arrangement of the engagement pins103 and 104, without need to employ electrical control, whose cost ishigh, and thus at low cost.

FIGS. 15 to 19 show a third embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the thirdembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes three energy-absorbingmembers 111, 112, and 113 provided in the upper support mechanism A; anengagement hook 114 provided on the steering column 12; and anenergy-absorbing member 115 provided on the lower support mechanism B.Structural features other than the collision-energy-absorbing means forabsorbing secondary collision energy of the occupant H are substantiallyidentical with those of the above-described first embodiment and arethus denoted by common reference numerals, and repeated descriptionthereof is omitted.

The energy-absorbing members 111, 112, and 113 are iron bars andplastically deformed when the engagement hook 114 is engaged with themand moves frontward, thereby absorbing secondary collision energy. Theenergy-absorbing members 111, 112, and 113 are attached in array to thereinforcement plate 31B of the support bracket 31 in the upper supportmechanism A. Each of the energy-absorbing members 111, 112, and 113 isformed into a shape resembling the lying letter U that opens frontwardand includes portions extending between its intermediate region and itsfront ends along the axial direction of the steering column 12. As shownin FIG. 17, a rear end portion of each of the energy-absorbing members111, 112, and 113 is curved downward and thus can be engaged with theengagement hook 114 substantially at its center. A cutout 31 d is formedin the reinforcement plate 31B of the support bracket 31 in order toallow frontward movement of the engagement hook 114 engaged with theenergy-absorbing member(s) 111 (112 and 113).

The engagement hook 114 is provided on the steering column 12 in anupward projecting condition. When the steering column 12 tilts upwardand moves frontward from the condition of FIG. 15, the engagement hook114 can engage with the energy-absorbing member(s) 111 (112 and 113).Being engaged with the energy-absorbing member(s) 111 (112 and 113), theengagement hook 114 can plastically deform the energy-absorbingmember(s) 111 (112 and 113).

As shown in FIG. 18, the energy-absorbing member 115 provided in thelower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 115 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 115 is fixedly attached, at its one end portion 105 a, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured third embodiment, in the event of asecondary collision that accompanies a collision of the vehicle; forexample, when, as shown in FIG. 18, a secondary collision load is inputto the steering column 12 in the direction of the arrow (in thedirection of the column axis) via the steering shaft 11, the steeringcolumn 12 moves frontward along its axial direction. In this case, whilethe engagement hook 114 is engaged with none of the energy-absorbingmembers 111, 112, and 113, the energy-absorbing member 115 isplastically deformed by means of the collar 73. As a result, sincesecondary collision energy is absorbed by means of plastic deformationof only the energy-absorbing member 115 caused by the collar 73, anabsorption load for secondary collision energy is small.

In the event of a secondary collision that accompanies a collision ofthe vehicle; for example, when, as shown in FIG. 19, a secondarycollision load is input to the steering column 12 in the direction ofthe arrow (substantially in the horizontal direction) via the steeringshaft 11, the steering column 12 tilts upward in response to a secondarycollision load exerted in the direction of the arrow at the initialstage of the secondary collision and subsequently moves frontward alongits axial direction.

Thus, the engagement hook 114 is engaged with the bottomenergy-absorbing member 111 to thereby plastically deform theenergy-absorbing member 111, while the energy-absorbing member 115 isplastically deformed by means of the collar 73. In this case, sincesecondary collision energy is absorbed by means of plastic deformationof the energy-absorbing member 111 caused by the engagement hook 114 andplastic deformation of the energy-absorbing member 115 caused by thecollar 73, an absorption load for secondary collision energy is largerthan that in the case of FIG. 18.

In the case where, as a result of input of a large secondary collisionload in the direction of the arrow of FIG. 19, the steering column 12tilts upward more than in the condition shown in FIG. 19 andsubsequently moves frontward along its axial direction, the engagementhook 114 is engaged with the energy-absorbing members 111 and 112 or 111to 113 to thereby plastically deform the energy-absorbing members 111and 112 or 111 to 113, while the energy-absorbing member 115 isplastically deformed by means of the collar 73. In this case, sincesecondary collision energy is absorbed by means of plastic deformationof the energy-absorbing members 111 and 112 or 111 to 113 caused by theengagement hook 114 and plastic deformation of the energy-absorbingmember 115 caused by the collar 73, an absorption load for secondarycollision energy is larger than that in the case of FIG. 19.

As described above, according to the third embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmembers 111, 112, and 113 and the engagement hook 114 changes anabsorption load for secondary collision energy in accordance with thedirection and load of a secondary collision of the occupant H with thesteering system. In other words, the third embodiment can bemechanically implemented by means of appropriately setting, for example,the shape of the energy-absorbing members 111, 112, and 113 and theshape and arrangement of the engagement hook 114, without need to employelectrical control, whose cost is high, and thus at low cost.

FIGS. 20 to 24 show a fourth embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the fourthembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes laterally pairedenergy-absorbing members 121 and 122, a cam 123, and an energy-absorbingmember 124 provided on the lower support mechanism B. Structuralfeatures other than the collision-energy-absorbing means for absorbingsecondary collision energy of the occupant H are substantially identicalwith those of the above-described first embodiment and are thus denotedby common reference numerals, and repeated description thereof isomitted.

The laterally paired energy-absorbing members 121 and 122 are ironplates and plastically deformed when moving frontward while beingengaged with the cam 123, thereby absorbing secondary collision energy.The laterally paired energy-absorbing members 121 and 122 are integrallyformed with corresponding laterally paired vertical walls of thecolumn-side bracket 62 in the lower support mechanism B and extend inthe front-rear direction while being slightly inclined upward inrelation to the axial direction of the steering column 12.

The cam 123 is employed in place of the bushes 71, 72 and the collar 73of the connection means 70. The cam 123 is nonrotatably attached to asquare portion 74 a of the bolt 74 at such an angle that one of fourflat portions 123 a formed on its outer surface in a diagonally facingcondition is substantially aligned with the longitudinal direction ofthe laterally paired elongated holes 62 a provided in the column-sidebracket 62. At a front end portion of each of the laterally pairedelongated hole 62 a provided in the column-side bracket 62, the cam 123is rotatable in relation to the elongated holes 62 a. At a portion ofeach of the elongated holes 62 a other than the front end portion, thecam 123 can be engaged with the energy-absorbing members 121, 122, and124. Being engaged with the energy-absorbing members 121 and 122 and theenergy-absorbing member 124, the cam 123 can plastically deform theenergy-absorbing members 121, 122, and 124.

As shown in FIG. 23 or 24, the energy-absorbing member 124 is anelongated plate. When the steering column 12 moves frontward, theenergy-absorbing member 124 is engaged with the cam 123 and plasticallydeformed to thereby absorb secondary collision energy. Theenergy-absorbing member 124 is fixedly attached, at its one end portion(not shown), to the column-side bracket 62; loops around the cam 123;and extends frontward (see FIG. 20).

According to the thus-configured fourth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle; forexample, when, as shown in FIG. 23, a secondary collision load is inputto the steering column 12 in the direction of the arrow (in thedirection of the column axis) via the steering shaft 11, the steeringcolumn 12 moves frontward along its axial direction. In this case, whilethe flat portions 123 a of the cam 123 are engaged with theenergy-absorbing members 121 and 122 (the energy-absorbing members 121and 122 are hardly plastically deformed by means of the cam 123), theenergy-absorbing member 124 is plastically deformed by means of the cam123. As a result, since secondary collision energy is absorbed by meansof plastic deformation of only the energy-absorbing member 124 caused bythe cam 123, an absorption load for secondary collision energy is small.

In the event of a secondary collision that accompanies a collision ofthe vehicle; for example, when, as shown in FIG. 24, a secondarycollision load is input to the steering column 12 in the direction ofthe arrow (substantially in the horizontal direction) via the steeringshaft 11, the steering column 12 tilts upward in response to a secondarycollision load exerted in the direction of the arrow at the initialstage of the secondary collision and subsequently moves frontward alongits axial direction.

Thus, corner portions of the cam 123 are engaged with theenergy-absorbing members 121 and 122 to thereby plastically deform theenergy-absorbing members 121 and 122, while the energy-absorbing member124 is plastically deformed by means of the cam 123. In this case, sincesecondary collision energy is absorbed by means of plastic deformationof the energy-absorbing members, 121, 122, and 124 caused by the cam123, an absorption load for secondary collision energy is larger thanthat in the case of FIG. 23.

In the case where, as a result of input of a large secondary collisionload in the direction of the arrow of FIG. 24, the steering column 12tilts upward more than in the condition shown in FIG. 24 andsubsequently moves frontward along its axial direction, the quantity ofplastic deformation of the energy-absorbing members 121 and 122increases with the quantity of upward tilting of the steering column 12.Thus, an absorption load for secondary collision energy increasesaccordingly.

As described above, according to the fourth embodiment, in the event ofa secondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmembers 121, 122, and 124 and the cam 123 changes an absorption load forsecondary collision energy in accordance with the direction and load ofa secondary collision of the occupant H with the steering system. Inother words, the fourth embodiment can be mechanically implemented bymeans of appropriately setting, for example, the shape and arrangementof the energy-absorbing members 121, 122, and 124 and the cam 123,without need to employ electrical control, whose cost is high, and thusat low cost.

FIGS. 25 to 31 show a fifth embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. The fifthembodiment employs a ball-type collision-energy-absorbing device ascollision-energy-absorbing means for absorbing secondary collisionenergy of the occupant H. The ball-type collision-energy-absorbingdevice includes a plurality of balls 131, a ring 132 for holding theballs 131, and a rod 133 capable of press-rotating the ring 132.

In the fifth embodiment, the steering shaft 11 is composed of an uppershaft 11 a and a lower shaft 11 b. The upper shaft 11 a and the lowershaft 11 b can axially extend and contract in relation to each other andcan transmit torque. The steering column 12 is composed of an uppercolumn 12 a and a lower column 12 b. The upper column 12 a and the lowercolumn 12 b can axially extend and contract in relation to each otherand support respectively the upper shaft 11 a and the lower shaft 11 brotatably and in an axially immovable condition.

The upper column 12 a is supported at a predetermined tilt angle to asteering mounting member, which is a portion of a vehicle body, by meansof the upper support mechanism Aa, in a tiltable condition and in such acondition as to be detachable frontward under a set load. The lowercolumn 12 b is supported at a predetermined tilt angle to the steeringmounting member, which is a portion of the vehicle body, by means of thelower support mechanism Ba, in a tiltable (pivotable) condition. Threeengagement grooves 12 b 1, 12 b 2, and 12 b 3 (see FIG. 31) are axiallyformed for each of the balls 131 on the outer circumferential surface ofthe lower column 12 b.

The engagement grooves 12 b 1, 12 b 2, and 12 b 3 differ in depth andare formed on the lower column 12 b in a circumferentially arrangedcondition. Initially, the balls 131 are engaged with the correspondingengagement grooves 12 b 1. The engagement grooves 12 b 1 are thedeepest; the engagement grooves 12 b 2 are the next deepest; and theengagement grooves 12 b 3 are the shallowest.

The balls 131 are of steel and held within the ring 132 at predeterminedcircumferential intervals. The balls 131 and the ring 132 are rotatableand axially movable in a unitary condition. When the balls 131, togetherwith the ring 132, move frontward in the axial direction, the balls 131can plastically deform the outer circumference of the lower column 12 balong the engagement grooves 12 b 1, 12 b 2, or 12 b 3.

The ring 132 has a plurality of spherical holes 132 b (see FIG. 31)formed along its inner circumference. The spherical holes 132 b areadapted to partially accommodate the corresponding balls 131. The ring132 is attached to the outer circumference of the lower column 12 b viathe balls 131. An arm 132 a is provided on the right-hand side of thering 132 and projects radially outward. The arm 132 a can be engagedwith the rod 133.

The rod 133 is fixedly attached to the steering mounting member andprojects downward. As shown in FIG. 28, when the lower column 12 b ofthe steering column 12 tilts upward by a predetermined amount a beyond atilt stroke L, the rod 133 is engaged with the arm 132 a to therebyrotate the ring 132 clockwise in FIG. 28.

According to the thus-configured fifth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle; forexample, when, as shown in FIG. 29, a secondary collision load is inputto the upper column 12 a of the steering column 12 in the direction ofthe arrow (in the direction of the column axis) via the upper shaft 11 aof the steering shaft 11, the upper column 12 a moves frontward alongits axial direction and pushes the ring 132 frontward.

In this case, the balls 131, together with the ring 132, move frontwardwhile being engaged with the corresponding deepest engagement grooves 12b 1, thereby plastically deforming the outer circumference of the lowercolumn 12 b along the engagement grooves 12 b 1. Since secondarycollision energy is absorbed by means of slight plastic deformation ofthe outer circumference of the lower column 12 b caused by the balls131, an absorption load for secondary collision energy is small.

In the event of a secondary collision that accompanies a collision ofthe vehicle; for example, when, as shown in FIG. 30, a secondarycollision load is input to the upper column 12 a of the steering column12 in the direction of the arrow (substantially in the horizontaldirection) via the upper shaft 11 a of the steering shaft 11, the upperand lower columns 12 a and 12 b of the steering column 12 tilt upward inresponse to a secondary collision load exerted in the direction of thearrow at the initial stage of the secondary collision and subsequentlymove frontward along their axial direction.

In the case where, at the initial stage of the secondary collision, thelower column 12 b tilts upward by the predetermined quantity α or morebeyond the tilt stroke L, the arm 132 a of the ring 132 is engaged withthe rod 133. As a result, as shown in FIG. 28( c) and FIG. 31, the ring132 is rotated clockwise. In this case, the balls 131 shift from thedeepest corresponding engagement grooves 12 b 1 to the shallowercorresponding engagement grooves 12 b 2 or 12 b 3 and subsequently movefrontward together with the ring 132 while being engaged with thecorresponding engagement grooves 12 b 2 or 12 b 3, thereby plasticallydeforming the outer circumference of the lower column 12 b along theengagement grooves 12 b 2 or 12 b 3. In this case, the outercircumference of the lower column 12 b is plastically deformed by meansof the balls 131 to a greater extent than in the case where the ring 132is not rotated, whereby secondary collision energy is absorbed. Thus, anabsorption load for secondary collision energy is larger than that inthe case where the ring 132 is not rotated.

As described above, according to the fifth embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the rod 133, the ring132, and the balls 131 changes an absorption load for secondarycollision energy in accordance with the direction and load of asecondary collision of the occupant H with the steering system. In otherwords, the fifth embodiment can be mechanically implemented by means ofappropriately setting, for example, the shape and arrangement of the rod133, the ring 132, the balls 131, and the engagement grooves 12 b 1 to12 b 3, without need to employ electrical control, whose cost is high,and thus at low cost.

FIGS. 32 to 36 show a sixth embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the sixthembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes an energy-absorbing member141 provided in the upper support mechanism A and an energy-absorbingmember 143 provided in the lower support mechanism B. Structuralfeatures other than the collision-energy-absorbing means for absorbingsecondary collision energy of the occupant H are substantially identicalwith those of the above-described first embodiment and are thus denotedby common reference numerals, and repeated description thereof isomitted.

The energy-absorbing member 141 is an iron plate and plasticallydeformed when moving frontward while being engaged with thereinforcement plate 31B of the support bracket 31 in the upper supportmechanism A, thereby absorbing secondary collision energy. Theenergy-absorbing member 141, together with a base plate 142 formed of aniron plate, is welded to the upper surface of the steering column 12.The energy-absorbing member 141 includes a bulge portion 141 a bulgingupward and extending from its intermediate portion to its rear endportion. The bulge portion 141 a extends along the axial direction ofthe steering column 12 and can be engaged with a curved lower endportion of the reinforcement plate 31B, which is bent to have anL-shaped cross section.

As shown in FIG. 32, the energy-absorbing member 143 provided in thelower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 143 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 143 is fixedly attached, at its one end portion, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured sixth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle,usually, in accordance with a secondary collision load input to thesteering column 12 via the steering shaft 11, the steering column 12tilts upward at the initial stage of the secondary collision andsubsequently moves frontward along its axial direction. In the casewhere an upward component of the secondary collision load input to thesteering column 12 is small, as shown in FIG. 35, the bulge portion 141a of the upper energy-absorbing member 141 is engaged with the curvedlower end portion of the reinforcement plate 31B of the support bracket31 and moves frontward. However, the upper energy-absorbing member 141may not be plastically deformed. In this case, the lowerenergy-absorbing member 143 is plastically deformed by means of thecollar 73. Since secondary collision energy is absorbed by means ofplastic deformation of only the energy-absorbing member 143 caused bythe collar 73, an absorption load for secondary collision energy issmall.

In the case where the upward component of the secondary collision loadinput to the steering column 12 is large, as shown in FIG. 36, the bulgeportion 141 a of the upper energy-absorbing member 141 may be engagedwith the curved lower end portion of the reinforcement plate 31B of thesupport bracket 31. In this case, the energy-absorbing member 141 movesfrontward while being plastically deformed. Since secondary collisionenergy is absorbed by means of plastic deformation of theenergy-absorbing member 141 caused by the reinforcement plate 31B andplastic deformation of the energy-absorbing member 143 caused by thecollar 73, an absorption load for secondary collision energy is largerthan that in the case where the upward component of load is small. Inthis case, the quantity of plastic deformation of the energy-absorbingmember 141 caused by the reinforcement member 31B varies dependently onthe upward component of the secondary collision load input to thesteering column 12.

As described above, according to the sixth embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmember 141 and the reinforcement plate 31B changes an absorption loadfor secondary collision energy in accordance with the direction and loadof a secondary collision of the occupant H with the steering system. Inother words, the sixth embodiment can be mechanically implemented bymeans of appropriately setting, for example, the shape of the bulgeportion 141 a of the energy-absorbing member 141 and the shape andarrangement of the reinforcement plate 31B, without need to employelectrical control, whose cost is high, and thus at low cost.

FIGS. 37 to 42 show a seventh embodiment of the impact-absorbingsteering column apparatus according to the present invention. In theseventh embodiment, collision-energy-absorbing means for absorbingsecondary collision energy of the occupant H includes anenergy-absorbing member 151 provided in the upper support mechanism Aand an energy-absorbing member 153 provided in the lower supportmechanism B. Structural features other than thecollision-energy-absorbing means for absorbing secondary collisionenergy of the occupant H are substantially identical with those of theabove-described first embodiment and are thus denoted by commonreference numerals, and repeated description thereof is omitted.

The energy-absorbing member 151 is an iron plate and plasticallydeformed when moving frontward while being engaged with thereinforcement plate 31B of the support bracket 31 in the upper supportmechanism A, thereby absorbing secondary collision energy. Theenergy-absorbing member 151, together with a base plate 152, is weldedto the upper surface of the steering column 12. The energy-absorbingmember 151 assumes an arcuate cross-sectional shape so as to be curvedsimilarly to the outer circumference of the steering column 12 with apredetermined gap held therebetween. An upper surface of theenergy-absorbing member 151 extending from its intermediate portion toits rear end portion can be engaged with a curved lower end portion ofthe reinforcement plate 31B, which is bent to have an L-shaped crosssection.

The base plate 152 is an iron plate and adapted to form a space (a spacethat enables plastic deformation of the energy-absorbing member 151)between the steering column 12 and the energy-absorbing member 151. Thebase plate 152 assumes an arcuate cross-sectional shape so as to becurved similarly to the outer circumference of the steering column 12.As shown in FIG. 38, the base plate 152 has a cutout that assumes arectangular shape as viewed in plane. The cutout is formed in a regionextending from an intermediate portion of the base plate 152 to a rearend portion of the base plate 152.

As shown in FIGS. 37 and 38, the energy-absorbing member 153 provided inthe lower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 153 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 153 is fixedly attached, at its one end portion, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured seventh embodiment, in the event of asecondary collision that accompanies a collision of the vehicle,usually, in accordance with a secondary collision load input to thesteering column 12 via the steering shaft 11, the steering column 12tilts upward at the initial stage of the secondary collision andsubsequently moves frontward along its axial direction. In the casewhere an upward component of the secondary collision load input to thesteering column 12 is small, as shown in FIG. 41, the upperenergy-absorbing member 151 is engaged with the curved lower end portionof the reinforcement plate 31B of the support bracket 31 and movesfrontward. However, the upper energy-absorbing member 151 may not beplastically deformed. In this case, the lower energy-absorbing member153 is plastically deformed by means of the collar 73. Since secondarycollision energy is absorbed by means of plastic deformation of only theenergy-absorbing member 153 caused by the collar 73, an absorption loadfor secondary collision energy is small.

In the case where the upward component of the secondary collision loadinput to the steering column 12 is large, as shown in FIG. 42, a portionof the upper energy-absorbing member 151 may be engaged with the curvedlower end portion of the reinforcement plate 31B of the support bracket31. In this case, the energy-absorbing member 151 moves frontward whilebeing plastically deformed. Since secondary collision energy is absorbedby means of plastic deformation of the energy-absorbing member 151caused by the reinforcement plate 31B and plastic deformation of theenergy-absorbing member 153 caused by the collar 73, an absorption loadfor secondary collision energy is larger than that in the case where theupward component of load is small. In this case, the quantity of plasticdeformation of the energy-absorbing member 151 caused by thereinforcement member 31B varies dependently on the upward component ofthe secondary collision load input to the steering column 12.

As described above, according to the seventh embodiment, in the event ofa secondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmember 151 and the reinforcement plate 31B changes an absorption loadfor secondary collision energy in accordance with the direction and loadof a secondary collision of the occupant H with the steering system. Inother words, the seventh embodiment can be mechanically implemented bymeans of appropriately setting, for example, the shape of theenergy-absorbing member 151, the shape of the base plate 152, and theshape and arrangement of the reinforcement plate 31B, without need toemploy electrical control, whose cost is high, and thus at low cost.

FIGS. 43 to 50 show an eighth embodiment of the impact-absorbingsteering column apparatus according to the present invention. In theeighth embodiment, collision-energy-absorbing means for absorbingsecondary collision energy of the occupant H includes anenergy-absorbing member 161 provided in the upper support mechanism A, adeformable portion 31 e provided in the plate 31A of the support bracket31 in the upper support mechanism A, and an energy-absorbing member 165provided in the lower support mechanism B. Structural features otherthan the collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H are substantially identical withthose of the above-described first embodiment and are thus denoted bycommon reference numerals, and repeated description thereof is omitted.

The energy-absorbing member 161 is a thin iron plate andsqueeze-deformed when the steering column 12 moves frontward with theenergy-absorbing member 161 being engaged with the reinforcement plate31B of the support bracket 31 in the upper support mechanism A, therebyabsorbing secondary collision energy. The energy-absorbing member 161 isprovided on the upper surface of the steering column 12 in such a manneras to be movable in the direction of the column axis, by use of a guideplate 162, a holder 163, and a round bar 164. The energy-absorbingmember 161 has a projection 161 a projecting upward from its rear endportion. The projection 161 a can be engaged with an engagement hole 31f formed in the reinforcement palate 31B.

The guide plate 162 is an iron plate and allows the energy-absorbingmember 161 to move along the steering column 12 when theenergy-absorbing member 161 is squeeze-deformed. The guide plate 162 iswelded to the upper surface of the steering column 12. The holder 163 isan iron plate and causes squeeze-deformation of the energy-absorbingmember 161 in cooperation with the round bar 164. The holder 163 iswelded to an upper portion of the steering column 12 while straddling aportion of the energy-absorbing member 161 and a portion of the guideplate 162. The round bar 164 is made of iron and is incorporated in theholder 163 together with a portion of the energy-absorbing member 161.

The deformable portion 31 e provided on the plate 31A of the supportbracket 31 in the upper support mechanism A is formed by means offorming in the plate 31A an elongated hole 31 e 1 extending in thefront-rear direction. When an upward load exerted on the deformableportion 31 e from the collar 42 and the lock bolt 41 of the clamp means40 becomes a predetermined value or greater, the deformable portion 31 eis plastically deformed upward, thereby allowing the projection 161 a ofthe energy-absorbing member 161 to be fitted into the engagement hole 31f formed in the reinforcement plate 31B.

As shown in FIGS. 43 and 44, the energy-absorbing member 165 provided inthe lower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 165 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 165 is fixedly attached, at its one end portion, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured eighth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle,usually, in accordance with a secondary collision load input to thesteering column 12 via the steering shaft 11, the steering column 12tilts upward at the initial stage of the secondary collision andsubsequently moves frontward along its axial direction. In the casewhere an upward component of the secondary collision load input to thesteering column 12 is small, as shown in FIGS. 47 and 48, the deformableportion 31 e provided on the plate 31A of the support bracket 31 in theupper support mechanism A is not plastically deformed. While theprojection 161 a of the upper energy-absorbing member 161 is not engagedwith the engagement hole 31 f formed in the reinforcement plate 31B ofthe support bracket 31, the lower energy-absorbing member 165 isplastically deformed by means of the collar 73. In this case, sincesecondary collision energy is absorbed by means of plastic deformationof only the energy-absorbing member 165 caused by the collar 73, anabsorption load for secondary collision energy is small.

In the case where the upward component of the secondary collision loadinput to the steering column 12 is large, as shown in FIGS. 49 and 50,the deformable portion 31 e provided on the plate 31A of the supportbracket 31 receives an upward load equal to or greater than a set valuefrom the collar 42 and the lock bolt 41 of the clamp means 40 to therebybe plastically deformed upward. The projection 161 a of theenergy-absorbing member 161 is fitted into the engagement hole 31 fformed in the reinforcement plate 31B. As a result, as the steeringcolumn 12 moves frontward, the holder 163 and the round bar 164squeeze-deforms the energy-absorbing member 161. At the same time, thelower energy-absorbing member 165 is plastically deformed by means ofthe collar 73.

In this case, since secondary collision energy is absorbed by means ofsqueeze-deformation of the energy-absorbing member 161 caused by theholder 163 and the round bar 164 and plastic deformation of theenergy-absorbing member 165 caused by the collar 73, an absorption loadfor secondary collision energy is larger than that in the case where theupward component of load is small. In this case, squeeze-deformation ofthe energy-absorbing member 161 caused by the holder 163 and the roundbar 164 is substantially constant irrespective of variations in asecondary collision load input substantially horizontally to thesteering column 12.

As described above, according to the eighth embodiment, in the event ofa secondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmember 161, the guide plate 162, the holder 163, the round bar 164, andthe support bracket 31 in the upper support mechanism A changes anabsorption load for secondary collision energy in accordance with thedirection and load of a secondary collision of the occupant H with thesteering system. In other words, the eighth embodiment can bemechanically implemented by means of appropriately setting, for example,the shape of the projection 161 a of the energy-absorbing member 161,the shape of the holder 163, the shape of the round bar 164, and theshape and arrangement of the support bracket 31 in the upper supportmechanism A, without need to employ electrical control, whose cost ishigh, and thus at low cost.

FIGS. 51 to 58 show a ninth embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the ninthembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes an energy-absorbing member171 provided in the upper support mechanism A, the deformable portion 31e provided in the plate 31A of the support bracket 31 in the uppersupport mechanism A, and an energy-absorbing member 173 provided in thelower support mechanism B. Structural features other than thecollision-energy-absorbing means for absorbing secondary collisionenergy of the occupant H are substantially identical with those of theabove-described first embodiment and are thus denoted by commonreference numerals, and repeated description thereof is omitted.

The energy-absorbing member 171 is a thin iron plate and plasticallydeformed when moving frontward while being engaged with thereinforcement plate 31B of the support bracket 31 in the upper supportmechanism A, thereby absorbing secondary collision energy. Theenergy-absorbing member 171, together with a base plate 172, is weldedto the upper surface of the steering column 12. The energy-absorbingmember 171 includes a bulge portion 171 a bulging upward and extendingfrom its intermediate portion to its rear end portion. The bulge portion171 a extends along the axial direction of the steering column 12 andcan be engaged with a curved lower end portion of the reinforcementplate 31B, which is bent to have an L-shaped cross section.

The deformable portion 31 e provided on the plate 31A of the supportbracket 31 in the upper support mechanism A is formed by means offorming in the plate 31A the elongated hole 31 e 1 extending in thefront-rear direction. When the deformable portion 31 e receives anupward load equal to or greater than a set value from the collar 42 andthe lock bolt 41 of the clamp means 40, the deformable portion 31 e isplastically deformed upward, thereby allowing the bulge portion 171 a ofthe energy-absorbing member 171 to be engaged with the curved lower endportion of the reinforcement plate 31B.

As shown in FIGS. 51 and 52, the energy-absorbing member 173 provided inthe lower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 173 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 173 is fixedly attached, at its one end portion, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured ninth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle,usually, in accordance with a secondary collision load input to thesteering column 12 via the steering shaft 11, the steering column 12tilts upward at the initial stage of the secondary collision andsubsequently moves frontward along its axial direction. In the casewhere the upward component of the secondary collision load input to thesteering column 12 is small, as shown in FIGS. 55 and 56, the deformableportion 31 e provided on the plate 31A of the support bracket 31 in theupper support mechanism A is not plastically deformed; and the bulgeportion 171 a of the upper energy-absorbing member 171 is engaged withthe curved lower end portion of the reinforcement plate 31B of thesupport bracket 31, but is not plastically deformed. In this case, thelower energy-absorbing member 173 is plastically deformed by means ofthe collar 73. Since secondary collision energy is absorbed by means ofplastic deformation of only the energy-absorbing member 173 caused bythe collar 73, an absorption load for secondary collision energy issmall.

In the case where the upward component of the secondary collision loadinput to the steering column 12 is large, as shown in FIGS. 57 and 58,the deformable portion 31 e provided on the plate 31A of the supportbracket 31 receives an upward load equal to or greater than a set valuefrom the collar 42 and the lock bolt 41 of the clamp means 40 to therebybe plastically deformed upward. The bulge portion 171 a of the upperenergy-absorbing member 171 is engaged with the curved lower end portionof the reinforcement plate 31B of the support bracket 31. As a result,as the steering column 12 moves frontward, the bulge portion 171 a ofthe upper energy-absorbing member 171 is plastically deformed by meansof the reinforcement plate 31B of the support bracket 31. At the sametime, the lower energy-absorbing member 173 is plastically deformed bymeans of the collar 73.

In this case, since secondary collision energy is absorbed by means ofplastic deformation of the energy-absorbing member 171 caused by thereinforcement plate 31B of the support bracket 31 and plasticdeformation of the energy-absorbing member 165 caused by the collar 73,an absorption load for secondary collision energy is larger than that inthe case where the upward component of load is small. In this case, thequantity of plastic deformation of the energy-absorbing member 171caused by the reinforcement member 31B of the bracket 31 variesdependently on the upward component of the secondary collision loadinput to the steering column 12.

As described above, according to the ninth embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmember 171 and the support bracket 31 in the upper support mechanism Achanges an absorption load for secondary collision energy in accordancewith the direction and load of a secondary collision of the occupant Hwith the steering system. In other words, the ninth embodiment can bemechanically implemented by means of appropriately setting, for example,the shape of the bulge portion 171 a of the energy-absorbing member 171and the shape and arrangement of the support bracket 31 in the uppersupport mechanism A, without need to employ electrical control, whosecost is high, and thus at low cost.

FIGS. 59 to 64 show a tenth embodiment of the impact-absorbing steeringcolumn apparatus according to the present invention. In the tenthembodiment, collision-energy-absorbing means for absorbing secondarycollision energy of the occupant H includes an energy-absorbing member181 provided in the upper support mechanism A, a squeezing plate 31Cprovided on the reinforcement plate 31B of the support bracket 31 in theupper support mechanism A, and an energy-absorbing member 183 providedin the lower support mechanism B. Structural features other than thecollision-energy-absorbing means for absorbing secondary collisionenergy of the occupant H are substantially identical with those of theabove-described first embodiment and are thus denoted by commonreference numerals, and repeated description thereof is omitted.

The energy-absorbing member 181 is a thin iron plate andsqueeze-deformed when the steering column 12 moves frontward with theenergy-absorbing member 181 being engaged with the squeezing plate 31Cprovided on the reinforcement plate 31B of the support bracket 31 in theupper support mechanism A, thereby absorbing secondary collision energy.The energy-absorbing member 181 is welded, at its front end portion, tothe upper surface of the steering column 12. The energy-absorbing member181 includes a curved portion 181 a located in its axially intermediateregion, curved upward, and adapted to accommodate a round bar 182, andlaterally paired arm portions 181 b for restricting lateral movement ofthe round bar 182. The curved portion 181 a, which accommodates theround bar 182, can be engaged with an engagement hole 31 g formed in thesqueezing plate 31C by means of being fitted into the engagement hole 31g.

The squeezing plate 31C provided on the reinforcement plate 31B of thesupport bracket 31 in the upper support mechanism A is an iron plate andcauses squeeze-deformation of the energy-absorbing member 181 incooperation with the round bar 182. The squeezing plate 31C is welded tothe lower surface of the reinforcement plate 31B. The round bar 182 is asolid iron rod; is incorporated in the curved portion 181 a of theenergy-absorbing member 181; and is movable along the upper surface ofthe steering column 12 in the direction of the column axis.

As shown in FIGS. 59 and 60, the energy-absorbing member 183 provided inthe lower support mechanism B is an elongated plate. When the steeringcolumn 12 moves frontward, the energy-absorbing member 183 is engagedwith the collar 73 of the connection means 70 and plastically deformedto thereby absorb secondary collision energy. The energy-absorbingmember 183 is fixedly attached, at its one end portion, to thecolumn-side bracket 62 in the lower support mechanism B; loops aroundthe collar 73; and extends frontward.

According to the thus-configured tenth embodiment, in the event of asecondary collision that accompanies a collision of the vehicle,usually, in accordance with a secondary collision load input to thesteering column 12 via the steering shaft 11, the steering column 12tilts upward at the initial stage of the secondary collision andsubsequently moves frontward along its axial direction. In the casewhere an upward component of the secondary collision load input to thesteering column 12 is small, as shown in FIG. 63, while the curvedportion 181 a of the upper energy-absorbing member 181 and the round bar182 are slightly engaged with the engagement hole 31 g of the squeezingplate 31C provided on the reinforcement plate 31B of the support bracket31, the upper energy-absorbing member 181 is drawn frontward as a resultof frontward movement of the steering column 12. In this case, sincesecondary collision energy is absorbed by means of slightsqueeze-deformation of the energy-absorbing member 181 caused by thesqueezing plate 31C and the round bar 182 and plastic deformation of theenergy-absorbing member 183 caused by the collar 73, an absorption loadfor secondary collision energy is small.

In the case where the upward component of the secondary collision loadinput to the steering column 12 is large, as shown in FIG. 64, while thecurved portion 181 a of the upper energy-absorbing member 181 and theround bar 182 are sufficiently engaged with the engagement hole 31 g ofthe squeezing plate 31C provided on the reinforcement plate 31B of thesupport bracket 31, the upper energy-absorbing member 181 is drawnfrontward as a result of frontward movement of the steering column 12.Thus, the squeezing plate 31C and the round bar 182 cause theenergy-absorbing member 181 to be sufficiently squeeze-deformed, and thelower energy-absorbing member 1183 is plastically deformed by means ofthe collar 73.

In this case, since secondary collision energy is absorbed by means ofsufficient squeeze-deformation of the energy-absorbing member 181 causedby the squeezing plate 31C and the round bar 182 and plastic deformationof the energy-absorbing member 183 caused by the collar 73, anabsorption load for secondary collision energy is larger than that inthe case where the upward component of load is small. In this case, thequantity of squeeze-deformation of the energy-absorbing member 181caused by the squeezing plate 31C and the round bar 182 variesdependently on the upward component of the secondary collision loadinput to the steering column 12.

As described above, according to the tenth embodiment, in the event of asecondary collision of the occupant H with the steering system,energy-absorption-load-changing means including the energy-absorbingmember 181, the round bar 182, and the squeezing plate 31C provided onthe reinforcement plate 31B of the support bracket 31 in the uppersupport mechanism A changes an absorption load for secondary collisionenergy in accordance with the direction and load of a secondarycollision of the occupant H with the steering system. In other words,the tenth embodiment can be mechanically implemented by means ofappropriately setting, for example, the shape of the energy-absorbingmember 181, the shape of the round bar 182, and the shape andarrangement of the squeezing plate 31C provided on the reinforcementplate 31B of the support bracket 31 in the upper support mechanism A,without need to employ electrical control, whose cost is high, and thusat low cost.

1. An impact-absorbing steering column apparatus comprisingcollision-energy-absorbing means for absorbing secondary collisionenergy of an occupant in the event of a collision of a vehicle, thecollision-energy-absorbing means comprisingenergy-absorption-load-changing means for changing an absorption loadfor the secondary collision energy, and theenergy-absorption-load-changing means being adapted to change theabsorption load in accordance with displacement of a steering column inat least a first direction when a secondary collision of the occupantwith a steering column occurs in a first direction and a seconddirection when the secondary collision of the occupant with the steeringcolumn occurs in a second direction.
 2. An impact-absorbing steeringcolumn apparatus comprising collision-energy-absorbing means forabsorbing secondary collision energy of an occupant in the event of acollision of a vehicle, the collision-energy-absorbing means comprisingenergy-absorption-load-changing means for changing an absorption loadfor the secondary collision energy, and theenergy-absorption-load-changing means being adapted to change anabsorption load path in accordance with displacement of a steeringcolumn in a direction intersecting a direction of relative movement ofthe steering column for absorbing collision energy induced by asecondary collision of the occupant.
 3. An impact-absorbing steeringcolumn apparatus as described in claim 1, wherein theenergy-absorption-load-changing means changes the absorption load inaccordance with a mode of displacement of the steering column.
 4. Animpact-absorbing steering column apparatus as described in claim 3,wherein the energy-absorption-load-changing means comprises anenergy-absorbing member, and engagement means capable of engaging withthe energy-absorbing member, and an engagement relation between theenergy-absorbing member and the engagement means varies in accordancewith a mode of displacement of the steering column, thereby changing theabsorption load.
 5. An impact-absorbing steering column apparatus asdescribed in claim 4, wherein the engagement means is squeezing meansfor squeezing the energy-absorbing member; the energy-absorbing memberhas an energy-absorbing portion, which is squeezed by the squeezingmeans to thereby absorb energy; and an engagement relation between thesqueezing means and the energy-absorbing portion varies in accordancewith a mode of displacement of the steering column, thereby changing theabsorption load.
 6. An impact-absorbing steering column apparatus asdescribed in claim 4, wherein the engagement means is squeezing meansfor squeezing the energy-absorbing member; the energy-absorbing memberhas a plurality of energy-absorbing portions that differ in energyabsorption load in relation to the squeezing means; and an engagementrelation between the squeezing means and one of the plurality ofenergy-absorbing portions is selected in accordance with a mode ofdisplacement of the steering column, thereby changing the absorptionload.
 7. An impact-absorbing steering column apparatus as described inclaim 4, wherein the engagement means is squeezing means for squeezingthe energy-absorbing member; the squeezing means has a plurality ofsqueezing portions that differ in the quantity of squeeze in squeezingthe energy-absorbing member; and an engagement relation between theenergy-absorbing member and one of the plurality of squeezing portionsis selected in accordance with a mode of displacement of the steeringcolumn, thereby changing the absorption load.
 8. An impact-absorbingsteering column apparatus as described in claim 4, wherein theenergy-absorbing member is a linear member capable of engaging with theengagement means; the engagement means is engaged with or is not engagedwith the linear member in accordance with a mode of displacement of thesteering column, thereby changing the absorption load.
 9. Animpact-absorbing steering column apparatus as described in claim 4,wherein the energy-absorbing member is a plurality of linear memberscapable of engaging with the engagement means; the number of the linearmembers to be engaged with the engagement means varies in accordancewith a mode of displacement of the steering column, thereby changing theabsorption load.
 10. An impact-absorbing steering column apparatus asdescribed in claim 4, wherein the steering column comprises theenergy-absorbing member, a ball adapted to plastically deform theenergy-absorbing member, and ball support means for adjusting thequantity of plastic deformation to be effected by the ball; and the ballsupport means is moved in accordance with a mode of displacement of thesteering column in such a manner as to vary an engagement relationbetween the energy-absorbing member and the ball in accordance with themode, thereby changing the absorption load.
 11. An impact-absorbingsteering column apparatus as described in claim 4, wherein theenergy-absorbing member has an elongated groove having a predeterminedwidth; the engagement means is squeezing means assuming a special shapeand capable of being displaced in the elongated groove in relation tothe energy-absorbing member; and an engagement relation between thespecial-shape squeezing means and the elongated groove of theenergy-absorbing member varies in accordance with a mode of displacementof the steering column, thereby changing the absorption load.
 12. Animpact-absorbing steering column apparatus as described in claim 4,wherein an energy-absorbing member is provided on either avehicle-body-side member or the steering column, the energy-absorbingmember generating an energy absorption load by means of displacement inrelation to either the vehicle-body-side member or the steering columnon which the energy-absorbing member is provided; the engagement meanscapable of engaging with the energy-absorbing member is provided oneither the vehicle-body-side member or the steering column on which theenergy-absorbing member is not provided; and when the energy-absorbingmember is engaged with the engagement means in accordance with a mode ofdisplacement of the steering column, the mode of displacement changingdependently on a secondary collision, the energy-absorbing memberincrementally changes the absorption load by means of displacement inrelation to either the vehicle-body-side member or the steering columnon which the energy-absorbing member is provided.
 13. Animpact-absorbing steering column apparatus as described in claim 1,wherein the energy-absorption-load-changing means changes the absorptionload in accordance with displacement of the steering column, thedisplacement changing dependently on the direction of a secondarycollision of the occupant with the steering system.
 14. Animpact-absorbing steering column apparatus as described in claim 1,wherein the energy-absorption-load-changing means changes the absorptionload in accordance with displacement of the steering column, thedisplacement changing dependently on the direction of a secondarycollision of the occupant with the steering system at an initial stageof the secondary collision.
 15. An impact-absorbing steering columnapparatus as described in claim 1, wherein when a collision loadassociated with a secondary collision of the occupant with the steeringsystem is equal to or greater than a predetermined value, theenergy-absorption-load-changing means increases the absorption load. 16.An impact-absorbing steering column apparatus as described in claim 1,wherein the energy-absorption-load-changing means increases theabsorption load in accordance with such displacement that the steeringcolumn tilts upward as a result of a secondary collision of the occupantwith the steering system.
 17. An impact-absorbing steering columnapparatus as described in claim 1, wherein theenergy-absorption-load-changing means changes the absorption load inaccordance with a displaced position of the steering column, thedisplaced position changing dependently on the direction of a secondarycollision of the occupant with the steering system.
 18. Animpact-absorbing steering column apparatus as described in claim 1,wherein impact-absorbing means for absorbing a predetermined collisionload is provided separately from the collision-energy-absorbing means.19. An impact-absorbing steering column apparatus as described in claim1, wherein the collision-energy-absorbing means selectively produces theabsorption load, or changes the magnitude of the absorption load.
 20. Animpact-absorbing steering column apparatus as described in claim 1,wherein in accordance with a load pressing the steering column against avehicle-body-side member and a load of moving the steering column towardthe front of the vehicle, the loads changing dependently on a secondarycollision of the occupant with the steering system, deformation of anenergy-absorbing member provided on either the steering column or thevehicle-body-side member is passively changed by engagement meansprovided on either the steering column or the vehicle-body-side memberon which the energy-absorbing member is not provided, whereby theenergy-absorption-load-changing means changes the absorption load. 21.An impact-absorbing steering column apparatus as described in claim 20,wherein the engagement means is formed on the vehicle-body-side member;the energy-absorbing member is provided on the steering column inopposition to the engagement means and assumes an elongated shapeextending along an axis of the steering column; and the engagement meansprovided on the vehicle-body-side member causes the deformation of theenergy-absorbing member provided on the steering column.
 22. Animpact-absorbing steering column apparatus as described in claim 20,wherein only when a collision load imposed on the vehicle-body-sidemember from the steering column is equal to or greater than apredetermined value, abutment between the engagement means and theenergy-absorbing member is enabled.
 23. An impact-absorbing steeringcolumn apparatus as described in claim 1, wherein in the event of asecondary collision, the steering column is allowed to be displaced insuch a manner as to tilt toward a vehicle-body-side member.
 24. Animpact-absorbing steering column apparatus as described in claim 1,wherein the absorption load is increased with a load of pressing thesteering column against a vehicle-body-side member.
 25. Animpact-absorbing steering column apparatus as described in claim 1,wherein impact-absorbing means for absorbing a predetermined collisionload is provided separately from the collision-energy-absorbing means.